Another question related to brain/mind physicalism...

[derrick09]

Over the past few years that I've glanced at this issue, I distinctively remember reading (from Christian apologists) about a major scientific study that shows that each of us over every seven to twelve years replace every cell in our body. Thus, they conclude shows that if our mind was indeed our brain, we would drastically change our personality and be unable to properly recall childhood or distant memories of our past, which thus shows that mind/brain physicalism is false. But not too long ago, I remember reading on a secular science web site that this claim that we replace EVERY cell in our bodies is a myth. They claim that the real data shows that we replace every cell in our bodies except certain parts of our neurological system. Now with that stated, I was wanting to ask you all the following....

If you all are aware of the studies that discuss human cell replacement over time, do you know specifically what parts of the neurological system endure our entire life span? Is it something that if proven would demolish the concept of the immaterial mind or is this something more of a trivial part of the brain that has no major effect on our actual thinking process? This is very crucial because for example if it is demonstrated scientifically that our brain cells endure our entire lifetimes, that could practically destroy the vast majority of immaterial mind theories and thus give huge evidence for physicalism, which in turns, really does allot to undermine the case for Christian theism in my opinion. Not to mention, this could also destroy the notion of free will. But if any fellow Apologist can help shine some details on this human cell replacement studies that would be a great help. Thank you all again for your time. God bless.

[zoegirl]

Over the past few years that I've glanced at this issue, I distinctively remember reading (from Christian apologists) about a major scientific study that shows that each of us over every seven to twelve years replace every cell in our body. Thus, they conclude shows that if our mind was indeed our brain, we would drastically change our personality and be unable to properly recall childhood or distant memories of our past, which thus shows that mind/brain physicalism is false. But not too long ago, I remember reading on a secular science web site that this claim that we replace EVERY cell in our bodies is a myth. They claim that the real data shows that we replace every cell in our bodies except certain parts of our neurological system. Now with that stated, I was wanting to ask you all the following....

If you all are aware of the studies that discuss human cell replacement over time, do you know specifically what parts of the neurological system endure our entire life span? Is it something that if proven would demolish the concept of the immaterial mind or is this something more of a trivial part of the brain that has no major effect on our actual thinking process? This is very crucial because for example if it is demonstrated scientifically that our brain cells endure our entire lifetimes, that could practically destroy the vast majority of immaterial mind theories and thus give huge evidence for physicalism, which in turns, really does allot to undermine the case for Christian theism in my opinion. Not to mention, this could also destroy the notion of free will. But if any fellow Apologist can help shine some details on this human cell replacement studies that would be a great help. Thank you all again for your time. God bless.

Neurons do not divide (or they repair themselves very very slowly), which is why damage to them results in permanent paralysis or brain damage. our learning manifests itself in neurological connections, extensions called dendrites connect to other neurons. These connections are what established our memories, our emotions, our learning, etc.

So we do not replace our brain cells.

Some parts in the body do replace themselves very quickly, such as the stomach and intestianl linings, as well as the skin....others, like muscle and neurons, divide very slowly or not at all. Most of the body is somewhere in the middle....

some parts

[derrick09]

So thus,we can conclude then, the evidence is clearly on the atheistic side of brain/mind physicalism and thus or mind is indeed our brain correct?

[zoegirl]

No, why do you say that? merely because this is the mechanism through which we learn has no bearing on the existence of God

[derrick09]

No, why do you say that? merely because this is the mechanism through which we learn has no bearing on the existence of God

Let's see, I'm by no means an expert in neuroscience, I"m just frightened by the fact that the consensus is among many neuroscientists is that the brain/mind are one and the same which thus, may have destructive implications to our faith and worldview. You said in the above quote that the area where no cell replication goes on is only in the area where learning takes place? I was curious, what about the areas and mechanisms of the brain that control sences, personality, or memory storage of previously learned things? Is cell replication indeed going in those areas or are they just like the area where learning takes place? If it can be shown scientifically that cell replication is going on in THOSE mechanisms and areas than it may mean that substance dualism, possibly other forms of dualsim, and the case for the immaterial soul still has a good surviving chance as a reasonable position. If you could elaborate or contribute anymore please do so. Thank you zoegirl for your input.

[Jac3510]

Derreck,

May I offer a small piece of advice? (If not, stop reading here, because here it comes! )

Don't confuse substance dualism with Christianity. It may be that substance dualism is true. It is certainly becoming a popular position among Christian philosophers thanks to Moreland, Craig, Plantinga, etc. But even if it were disproven (as I think it was over two thousand years ago before Christianity even came onto the scene!), Christianity isn't affected, because the traditional Christian position is not substance dualism.

This is a philosophical issue, not a theological one. Christianity can certainly accommodate substance dualism, but it isn't limited to it.

With THAT said, let me be an advocate for substance dualism, only in that I don't think the objection you are raising here affects it. How does it follow that because our brain cells don't change that therefore our mind is a material thing? If the mind is somehow "anchored" to that part of our brain (indeed, it has to be anchored somewhere!), then what does it matter if the anchor does or doesn't change? You can't assume something about the nature of the soul just because the physical makeup of the physical brain!

Now, this DOES mean that you cannot use the argument you originally posted, that since ALL of our body cells change yet we stay the same, there must be an immaterial substance that stores our memories (lest they all be lost). However, you can still use the argument if you nuance it differently. If you use the argument like Aristotle and Aquinas put it, you'll have no issues. Let me give you an illustration:

Suppose I buy a car tomorrow. Suppose, now, I replace the tires. Then the rims. Then the exhaust system. Then, I put in a bigger engine, better seats, etc. Suppose I have a wreck, and replace the body, paint and glass. Suppose in ten years, a new frame comes out that is stronger, and I just have such an emotional attachment to this car that it is worth it to upgrade for me, so I have that changed, too. Suppose, over ten years, I replace EVERY SINGLE PART OF THE CAR.

Is it still the same car?

OF COURSE! I just say that my car has had all its parts replaced at some point, but it is still the same car. If it were not, I could not say that it has had all of its parts replaced!

So, how is it that we can change as much as we do and yet still be the same? Who cares that some of our brain cells don't change. That's not what I'm asking. I change SO MUCH. How can I be the same person? To put it the old way, how can something change and yet still be the same thing?

There are several ways to answer that. You can go with the classical form/matter distinction of Aristotle and Aquinas, which leads you to composite dualism (not substance dualism); you can argue that the body is just clothing for something on the inside--the soul--which would lead you to substance dualism. Just because I change all my clothes except my shirt doesn't mean I'm no longer a person, does it? Why, then, if substance dualism is true, can't the soul change all its clothes except one of them, in this case, certain brain cells?

And if favor of our view is the fact that if physicalism is true, then it makes no sense to talk about thoughts at all. If EVERYTHING is caused by the laws of nature, then that includes your thoughts on some level. You do not choose anything. Everything is determined by the laws of nature. Self-consciousness is just an illusion, as is free will. "You" don't exist. "You" are just a collection of atoms acting according to the laws of nature. There is nothing inside of you that can act as it wills, because there is nothing inside of you that is not forced to do what it is doing by the laws of physics.

The fact, then, that you ARE self-conscious and that you CAN think and that you do have (relative) free will means that physicalism is, in some sense, NOT true. There must be a part of you that exists "outside" the laws of nature--that is, that can act independently of them--which we all call the soul, whatever we may understand it to be.

I hope this helps!

God bless

[BGoodForGoodSake]

You said in the above quote that the area where no cell replication goes on is only in the area where learning takes place? I was curious, what about the areas and mechanisms of the brain that control sences, personality, or memory storage of previously learned things? Is cell replication indeed going in those areas or are they just like the area where learning takes place?

You don't need to be a neurosurgeon. Just learn a little more about how the brain works.
Your assertion that these facts somehow leads to the conclusion that there is no God is quite a leap.

[waynepii]

I find the "other side" of this question more interesting - namely "what is the role of the soul?". Consciousness? Emotions? Personality? Behavior? Memory? Conscience? Something else?

Consciousness, emotions, personality, behavior, memory and conscience are all affected by pharmaceuticals or insult to the brain (by trauma, disease, hypoxia, etc), so they appear to be functions of the physical body, primarily the brain. So what IS the role of the soul?

[jlay]

Wayne, you are a soul.